Evaluation of the effectiveness of off-pump coronary artery bypass grafting in high-risk patients: An observational study

Background. Coronary artery bypass grafting in high-risk patients carries substantial morbidity. We compared the effectiveness of off-pump revascularization with that of conventional coronary artery bypass grafting using cardiopulmonary bypass and cardioplegic arrest in consecutive high-risk patients. Methods. From April 1996 to December 2000, clinical data for consecutive patients undergoing coronary artery revascularization were prospectively entered into a database. Data were extracted for all patients considered to be high risk, defined as the presence of one or more of ten adverse prognostic factors. Hospital mortality and early morbidity were compared between two groups of patients, the on-pump and off-pump groups. Results. The study group comprised 1,570 consecutive high-risk patients, 332 (21.1%) of whom underwent an off-pump operation. Patients in the on-pump group had fewer high-risk factors and lower Parsonnet scores and were less likely to be 75 years of age or older, to have peripheral vascular disease or hypercholesterolemia, or to have sustained a previous transient ischemic attack. However, they were more likely to be assigned to a higher Canadian Cardiovascular Society class and had more extensive coronary artery disease and were more likely to have unstable angina, to require urgent or emergency operations, and to receive more grafts than those undergoing off-pump procedures. Unadjusted odds ratios for intensive care unit or high-dependency unit stay, total length of stay, blood loss of more than 1,000 mL, postoperative hemoglobin and transfusion requirement all showed a highly significant benefit for the off-pump group (p less than or equal to 0.005; odds ratios, 0.33 to 0.65). After adjustment for prognostic variables, odds ratios remained essentially unaltered (adjusted odds ratio estimates 0.36 to p < 0.05) except for blood loss of more than 1,000 mL (adjusted odds ratio estimate, 0.82; p = 0.22). Sensitivity analyses confirmed the robustness of these findings. Conclusions. Off-pump coronary artery bypass grafting is safe, effective, and associated with reduced morbidity in high-risk patients compared with conventional coronary artery revascularization.